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Introduction

This unit looks at three different uses of genetic testing: pre-natal diagnosis, childhood testing and adult testing. Such tests provide genetic information in the form of a predictive diagnosis, and as such are described as predictive tests. Pre-natal diagnosis uses techniques such as amniocentesis to test fetuses in the womb. For example, it is commonly offered to women over 35 to test for Down's syndrome. Childhood testing involves testing children for genetic diseases that may not
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1.7.1 Research methods in context

Any established discipline has a tradition of practice. Many disciplines have established methodologies which prescribe the selection, combination and sequencing of the methods and techniques to be employed. Others select methods and techniques less prescriptively and borrow more broadly across domain boundaries. All disciplines require an appropriate application of methods, in order to ensure rigour. Hence, one key skill is the demonstration of an appropriate knowledge and competence
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1.1 Thoughts on a PhD

Entering students often think of a PhD as a ‘magnum opus’, a brilliant research project culminating in a great work. This is rather a demanding model, and few students win Nobel Prizes as a result of their doctoral studies. More realistically, a PhD is research training leading to a research qualification. The PhD is a passport to a research career.

There are other views of a PhD, as well. Getting a PhD can be a ‘rite of passage’, prerequisite to admission into the academic ‘t
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2.2 Why study ecology?

These days, bird watching is a popular leisure activity and in the past so were collecting insects, wild flowers and birds’ eggs (although such activities are not now recommended – indeed, they are often illegal – because of the potential damage they cause to flora and fauna). Some amateurs are or were truly experts in their fields. In fact, much of the original identification of the British flora and fauna was done by amateur naturalists. Many a Victorian vicar or other self-taught nat
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1.10 Changing sea-level

Sedimentary rocks reveal how environmental conditions in Britain's geological past were extremely different from those of the present day (in fact ‘Britain’, like the rest of the Earth's geography is transitory when viewed in terms of the very long span of geological time). As well as evidence from sedimentary rocks, recent landforms also indicate that in the more recent geological past (within the Quaternary Period), sea-level was not the same as it is at present.

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1.6 The formation of metamorphic rocks

Any type of rock can become a metamorphic rock if it is heated to temperatures of several hundred degrees Celsius, and/or if subjected to high pressure (because of the weight of overlying rocks). During metamorphism, the minerals making up the rock become chemically unstable, meaning that their constituent ions are redistributed. The result is that either large crystals grow at the expense of existing smaller ones, or a new set of minerals is formed. Generally speaking, the overall chemical c
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1.5.2 Sedimentary processes

Sedimentary grains are formed when the rocks at the Earth's surface are slowly broken up physically by exposure to wind and frost, and decomposed (chemically) by rainwater or biological action. These processes are collectively termed weathering. Once a rock has been broken up by weathering, the small rock fragments and individual mineral grains can be eroded from their place of origin by water, wind or glaciers and transported to be deposited elsewhere as roughly horizontal layers of sediment
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1.4.4 Classifying igneous rocks

To classify (i.e. to name) igneous rocks, geologists use three pieces of information in combination – the grain size and the identity and proportions of the minerals present. The identification of minerals in a rock relies on recognising their particular distinguishing features. Such features include colour, lustre (the way in which light is reflected from the mineral's surface) and shape. The way in which certain minerals break apart along preferred planes, a property known as cleavage, ca
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1.4.3 Chemical and mineral composition of igneous rocks

As well as varying in grain size (owing to different cooling rates), igneous rocks also vary in chemical composition and hence in the identity and proportions of minerals present. For instance, the common igneous rock granite contains (as part of the strict geological definition of the term ‘granite’) between 10% and 35% by volume of the mineral quartz (chemical composition silicon dioxide – SiO2). On the other hand, the igneous rock gabbro (Author(s): The Open University

1.4.1 Igneous rocks in the landscape

The rocks that erupt from volcanoes are called extrusive igneous rocks, simply because they are formed by the extrusion of magma on to the Earth's surface. Igneous rocks can also form deep underground, and these are called intrusive igneous rocks, because the magmas were intruded into pre-existing rocks and then slowly cooled. The reason that intrusive igneous rocks are now visible at the surface is that over many millions of years erosion has stripped away the overlying rocks.
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4.2 Definitions of ageing

The term ‘ageing’ carries a number of different meanings. It encompasses changes that occur at many levels, from the population down to the molecular. Even at a single level, ageing does not represent a single process, but many processes, which may operate independently. Therefore, the challenge of defining ageing is more complex than it might first
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3.1.2. After reading this article:

The chapter by Teesson et al. (2002) will have presented you with a clearly written initial orientation to addiction. The article introduced addiction at several different levels of explanation in what the authors term a ‘biopsy chosocial model’ (p. 47). Such an integrated model is at the heart of the app
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3.1 Addiction article 1

The first selected reading provides a wide ranging review of the theories associated with addiction illustrating how the subject can be investigated at a number of different levels of analysis. The second article explores one particular level further, the pharmacology of drug addiction, and asks why specific drugs are more likely to induce addictive behaviour.


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Introduction

We are used to seeing spectacular astronomical images in the press and on the internet. This unit gives an in-depth introduction to two of the most important instruments used to create these images and explore the science behind them – telescopes and spectographs.

This unit is drawn from the preparatory work for the practical residential school at the Observatori Astronomic de Mallorca. The unit image shows a student at work in one of the telescope domes at the Observatori.

This
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1.6 Conclusion

This unit has presented an overview of the ways in which organisms living in temperate habitats are adapted to survive the winter. The unit has shown how a limited set of environmental changes associated with the onset of winter can lead to a diversity of adaptations and therefore a large diversity of species.

On the basis of the examples discussed in this unit, we can identify four factors that contribute to the diversity of adaptive strategies for coping with winter.

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Introduction

From the moment that Galileo dropped two cannonballs of different sizes and weights from the top of the Leaning Tower of Pisa mankind has been fascinated by the impact of gravity. This unit looks at gravity, its impact on objects and how the energy involved in the movement of objects is dispersed or stored.

This unit is from our archive and is an adapted extract from How the universe works (S197) which is no longer taught by The Open University. If you want to study formally with us, yo
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3 Where do earthquakes occur?

How deep in the Earth do earthquakes occur? Most earthquake foci are within a few tens of kilometres of the surface. Earthquakes less than 70 km deep are classified as shallow-focus. Earthquakes with foci 70–300 km deep are classified as intermediate-focus and those below 300 km are deep-focus (Figure 7). Shallow-focus
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1.6.1 Introduction

The process of keeping up-to-date in your chosen subject area is useful for your studies and afterwards, for your own personal satisfaction, or perhaps in your career as part of your continuing professional development.

There are a great many tools available that make it quite easy to keep yourself up to date. You can set them up so that the information comes to you, rather than you having to go out on the web looking for it. Over the next few pages, you will be experimenting with some
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1.4.4 O is for Objectivity

One of the characteristics of ‘good’ information is that it should be balanced and present both sides of an argument or issue. This way the reader is left to weigh up the evidence and make a decision. In reality, we recognise that no information is truly objective.

This means that the onus is on you, the reader, to develop a critical awareness of the positions represented in what you read, and to take account of this when you interpret the information. In some cases, authors may be
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13 Post-compulsory science education

In a speech to the Institute of Economic Affairs in 2001, the then UK Secretary of State for Education said:

Young people choosing vocational study will be able to see a ladder of progression that gives structure, purpose and expectation to their lives, in the same way that a future pathway is clear to those who leave school to gain academic A-levels and enter university. Over-16s in full-time education will be abl
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